Biologics Feature

3D Printed Cells Survive in Living Bodies

Biloine W. Young • Wed, April 5th, 2017

It is happening slowly but surely as scientists are demonstrating they can 3D print tissues or organs and successfully implant them in a living human being.

According to Clare Scott, a writer for 3D Print Board.com, it is now possible to 3D print tissue that can survive and grow within animals. Blood vessels have been printed and implanted into rhesus monkeys and in mice. Two Swedish universities have gotten 3D printed human cartilage cells to survive and grow inside an animal.

Paul Gatenholm,, Ph.D., a professor of biopolymer technology at Chalmers University of Technology in Gotenburg, Sweden, adjunct professor of biomaterial engineering at Virginia Polytechnic Institute in Blacksburg, Virginia, and the co-founder of CELLINK, used a CELLINK bioprinter to 3D print a construct formed from hydrogel mixed with human cartilage cells. The construct was immediately implanted in mice.

Not only did the cartilage tissue survive and grow, it vascularized, formed its own blood vessels.

The fact that it was implanted into the mice immediately after printing was significant. In previous studies researchers had grown the cartilage for a time in the lab before implanting it. Lars Kölby, M.D., Ph.D., senior lecturer at Sahlgrenska Academy and specialist consultant with the Department of Plastic Surgery at Sahlgrenska University Hospital described the formation of structures in bioprinted tissue.

“What we see after 60 days is something that begins to resemble cartilage. It is white and the human cartilage cells are alive and producing what they are supposed to,” he said. “We have also been able to stimulate the cartilage cells by adding stem cells, which clearly promoted further cell division.”

According to Kölby, much of the project’s success is due to the collaboration between scientists of different disciplines.

“Often, it is like this: we clinicians work with problems and researchers work with solutions,” he said. “If we can come together, there is a chance of actually solving some of the problems we are wrestling with—and in this way, patients benefit from the research.”

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Custom 3D Printer Used to Print Living Tissue

Elizabeth Hofheinz, M.P.H., M.Ed. • Wed, February 24th, 2016

Armed with funding from the Armed Forces Institute of Regenerative Medicine, researchers at Wake Forest Baptist Medical Center have designed a special 3D printer and proven that it is possible to print living tissue structures to replace injured or diseased tissue in patients.

As indicated in the February 15, 2016 news release, “Reporting in Nature Biotechnology, the scientists said they printed ear, bone and muscle structures. When implanted in animals, the structures matured into functional tissue and developed a system of blood vessels. Most importantly, these early results indicate that the structures have the right size, strength and function for use in humans.”

"This novel tissue and organ printer is an important advance in our quest to make replacement tissue for patients, " said Anthony Atala, M.D., director of the Wake Forest Institute for Regenerative Medicine (WFIRM) and senior author on the study, in the news release. "It can fabricate stable, human-scale tissue of any shape. With further development, this technology could potentially be used to print living tissue and organ structures for surgical implantation."

Dr. Atala told OTW, “Our research indicates the feasibility of printing bone, muscle and cartilage for patients. The results of this study bring us closer to the reality of using 3D printing to repair defects using the patient’s own engineered tissue. It is often frustrating for physicians to have patients receive a plastic or metal part during surgery knowing that the best replacement would have been the patient’s own tissue.”

According to the news release, “The Integrated Tissue and Organ Printing System (ITOP), developed over a 10-year period by scientists at the Institute for Regenerative Medicine, overcomes these challenges. The system deposits both bio-degradable, plastic-like materials to form the tissue "shape" and water-based gels that contain the cells. In addition, a strong, temporary outer structure is formed. The printing process does not harm the cells.”

“A major challenge of tissue engineering is ensuring that implanted structures live long enough to integrate with the body. The Wake Forest Baptist scientists addressed this in two ways. They optimized the water-based "ink" that holds the cells so that it promotes cell health and growth and they printed a lattice of micro-channels throughout the structures.

3D Printed Organs a Growing Possibility

Biloine W. Young • Mon, February 22nd, 2016

According to a report in the journal Nature Biotechnology, bioengineers have succeeded in developing a 3D tissue organ printer that can fabricate stable, human sized bones, muscle and cartilage using stem cells and polymer templates.

Anthony Atala, M.D., of Wake Forest School of Medicine in North Carolina, told Reuters Health that he and his colleagues “present an integrated tissue–organ printer (ITOP) that can fabricate stable, human-scale tissue constructs of any shape. The results of this study bring us closer to the reality of using 3D printing to repair defects using the patient’s own engineered tissue.”

Atala identified the problem of producing larger organs with 3D printing as one in which larger tissues require additional nutrition. He and his team resolved that problem, at least in part, by developing a process he calls the “integrated tissue and organ printing system, ” which produces a network of tiny channels that allows the printed tissue to be nourished after being implanted into a living animal. The polymer template eventually dissolves, he says, and is replaced by a viable organ.

As a demonstration, the research team “printed” a full-size human ear. The report in Sputnik International claimed that the ear cartilage looked like normal cartilage under a microscope, with blood vessels supplying the outer regions and with no circulation in the inner regions—which is typical of native cartilage. According to the article, the ear was later implanted into living mice. The ear was not rejected, became covered with blood vessels and “eventually became part of the animal’s system.”

The researchers caution that their new method is not yet ready for clinical use, but they are certain that it will not be long before it becomes widely applied in regenerative medicine.

3D Bioprinting Creates Blood Vessels

Biloine W. Young • Wed, March 23rd, 2016

A group of researchers has taken bio-printing to a new level. They have found a way to 3D bioprint thick vascularized tissue constructs composed of human stem cells, extracellular matrix, and circulatory channels lined with endothelial blood vessel cells. The resulting network of vasculature can channel fluids, nutrients and cell growth factors, for the first time, throughout tissues.

As Jennifer A. Lewis, Sc.D., senior author on the study and the Hansörg Wyss Professor of Biologically Inspired Engineering at Harvard’s John A. Paulson School for Engineering and Applied Sciences (SEAS), explained, "This latest work extends the capabilities of our multi-material bioprinting platform to thick human tissues, bringing us one step closer to creating architectures for tissue repair and regeneration."

Until now, scaling up human tissues built of cell types has been limited by an inability to embed life-sustaining vascular networks. Lewis and her team solved this problem by increasing the tissue thickness nearly tenfold. They combined vascular plumbing with living cells and an extracellular matrix which enabled the structures to function as living tissues. They showed that their 3D bioprinted tissues could function as living tissue architectures for upwards of six weeks.

"This research will help to establish the fundamental scientific understanding required for bioprinting of vascularized living tissues, " said Zhijian Pei, Ph.D., National Science Foundation Program Director for the Directorate for Engineering Division of Civil, Mechanical and Manufacturing Innovation, which funded the project.

According to Medical Press, Lewis uses a printed silicone mold to house and plumb the printed tissue structure. “Inside this mold, a grid of vascular channels is printed first, over which ink containing living stem cells is then printed. The inks are self-supporting and strong enough to hold shape as the structure's size increases with each layer of deposition. At intersections meeting within the foundational vascular grid, vertical vascular pillars are printed, which interconnect a network of microvessels. After printing, a liquid composed of fibroblasts and extracellular matrix fills in the open regions around the 3D printed tissue, cross linking the entire structure.”

The resulting structure has a quantity of blood vessels, and can be immediately perfused with nutrients to ensure survival of the cells.

Lab Bio-Prints Living Human Cartilage

Biloine W. Young • Fri, May 16th, 2014

In a major step forward researchers have succeeded in creating living, human cartilage that they grew on a laboratory chip. This development brings them closer to their ultimate goal which is creating replacement cartilage for patients with osteoarthritis. The process used bioprinting technology.

Leader of the research group is Rocky Tuan, Ph.D., director of the Center for Cellular and Molecular Engineering at the University of Pittsburgh School of Medicine. He said that creation of the artificial cartilage required three main elements: stem cells, biological factors to help the cells grow into cartilage, and a scaffold to give the tissue its shape. He said that his team’s process involved the extrusion of thin layers of stem cells embedded in a solution that retains its shape and provides the growth factors.

“We essentially speed up the development process by giving the cells everything they need, while creating a scaffold to give the tissue the exact shape and structure that we want, ” Tuan explained.

At present, the researchers are working to combine their 3D printing method with a nanofiber spinning technique they developed earlier. They hope combining the two methods will provide a more robust scaffold and allow them to create artificial cartilage that even more closely resembles natural cartilage. The ultimate vision is to give doctors a tool they can thread through a catheter to print new cartilage right where it’s needed in the patient’s body.

Tuan notes that artificial cartilage built using a patient’s own stem cells could offer enormous therapeutic potential. “We hope that the methods we're developing will really make a difference, both in the study of the disease and, ultimately, in treatments for people with cartilage degeneration or joint injuries, ” he said. “Ideally, we would like to be able to regenerate this tissue so people can avoid having to get a joint replacement, which is a pretty drastic procedure and is unfortunately something that some patients have to go through multiple times."

3D Bio-Ink Prints Cartilage and Bone

Biloine W. Young • Fri, July 1st, 2016

Researchers at the University of Bristol School of Cellular and Molecular Medicine have developed a stem cell bio-ink that can produce 3D printed cartilage and bone implants. The new stem cell ink contains two different polymers. One is a natural polymer extracted from seaweed. The second is a synthetic polymer that causes the ink to solidify when temperatures are raised. The seaweed-based material provides the structural support that is deemed necessary to sustain cell nutrients.

The project is directed by Adam Perriman, M.D. who explained that the custom formulation can be extruded by a 3D printer to form complex living 3D architectures, which will start to transform from a liquid into a gel at 37°C. Perriman said, “Designing the new bio-ink was extremely challenging. You need a material that is printable, strong enough to maintain its shape when immersed in nutrients, and that is not harmful to the cells. We managed to do this, but there was a lot of trial and error before we cracked the final formulation.”

Perriman noted that the synthetic material is only temporarily present. “What was really astonishing for us was when the cell nutrients were introduced, the synthetic polymer was completely expelled from the 3D structure, leaving only the stem cells and the natural seaweed polymer. This, in turn, created microscopic pores in the structure, which provided more effective nutrient access for the stem cells, ” he said.

The stem cells present in the bio-ink are purposefully adapted to be used for 3D bioprinted bone and cartilage implants. They achieved this by differentiating the stem cells into osteoblasts and chondrocytes which are cells that secrete bone and cartilage matrixes. Over a period of several weeks, according to Perriman, these materials grow into full-sized cartilage or bone structures that can be implanted.

The research group’s findings have been published in the journal of Advanced Healthcare Materials in a paper entitled “3D Bioprinting Using a Templated Porous Bioink.”